Dust shroud for abrading machine

ABSTRACT

A dust shroud for use with a vacuum source and an abrading machine having a rotating abrading wheel includes a dust shroud housing adapted to be connected to the vacuum source and mounted to the abrading machine. The dust shroud housing includes a front wall with a front opening through which the abrading wheel may be accessed. A sliding door is slidably mounted to the front wall of the dust shroud housing for selectively covering the front opening.

FIELD OF THE INVENTION

[0001] The present invention relates, in general, to shrouds or hoodsfor use with dust creating machines, and, in particular, to shrouds orhoods for use with abrading machines.

DISCUSSION OF RELATED ART

[0002] Dust creating machines such as grinding machines having grindingwheels are notorious for producing dust-laden air, grit and metalparticles during operation. Dust shrouds that partially envelop grindingwheels were developed in order to reduce some of this pollution bydrawing the dust, grit and metal particles through the dust shroud usinga remote vacuum operated exhaust system. By employing a dust shroudconnected to a vacuum, much of the dust-laden air resultant from wheelrotation during operational use can be effectively removed away from thearea of the grinding wheel and the machine operator. An example of sucha dust shroud is disclosed in U.S. Pat. No. 4,192,104 to Patenaude.

[0003] The manufactured dust shroud corresponding to U.S. Pat. No.4,192,104 is equipped with an inspection or access door that facilitatesinspection and changing of the grinding wheel. The access door is hingedto a front wall of the dust shroud housing at the top or sides of anopening in the front wall of the housing. A problem with a hinged accessdoor is that the workpiece or other equipment positioned directly infront of the hinged access door impedes an operator's ability to openthe door.

[0004] Another disadvantage of the hinged access door is that it canonly be maintained in either a fully closed position or a fully openposition (if specially rigged), and can not be maintained in a partiallyopened position. Quite often, it is desirable to have the hinged accessdoor at least partially open during operation of the grinding wheel inorder to surface grind certain workpieces or to inspect the wheel.Because the hinged door can not be maintained in a partially openedposition, when it is desirable for the hinged door to be in a partiallyopened position, the hinged door must be rigged so that it is in a fullyopen position. Most of the suction power that is provided by the vacuumsource is lost when the hinged door is in the fully open position,rendering the shroud ineffective. Further, with the hinged door in thefully open position, the operator's personal safety is compromisedduring use because the grinding wheel is not covered and the operator'shealth is compromised because dust, grit and metal particles are allowedto blow out of the opening in the front wall of the housing, into theoperator. Therefore, the present inventor has recognized a need existsfor an adjustable dust shroud access door that is capable of beingselectively positioned for a variety of partially opened conditions.

[0005] A further disadvantage of the manufactured dust shroudcorresponding to U.S. Pat. No. 4,192,104 is that it is made by a sandcasting process. Sand casting requires a new mold construction for eachshroud produced and necessitates a considerable amount of clean up. As aresult, the sand casting manufacturing process is slow, labor intensiveand costly. Also, the sand casting process is incapable of producing alight-weight shroud construction for several reasons. First, larger andthicker amounts of molten material are required to prevent the moltenmaterial from inadvertently hardening during introduction of the moltenmaterial into the mold. Second, the sand casting process is incapable ofproducing thin wall sections, which are required to produce a lighterweight dust shroud. The present inventor has recognized that alight-weight shroud would be easier to handle and extend the life of allgrinding machine components prone to premature wear and failure causedby unnecessarily heavy dust shrouds.

[0006] In addition, the rough, porous sand cast finish on the dustshroud has proven to be detrimental to the performance of the shroudbecause it causes the particles of dust, grit and metal to stick to theporous walls of the interior vacuum channels. Inevitably, the dust, gritand metal build-up causes a slower air speed of dust-laden air throughthe shroud, resulting in a reduction in the interior volume of thevacuum channels of the shroud. Occasionally, a complete restriction ofthe vacuum channels and a loss of all suction power occurs if thehousing is not effectively unclogged. Once the housing begins to clogup, it is difficult or impossible to service since it is a one-piecedesign and can not be taken apart for a proper cleaning. Consequently,the present inventor has recognized a need exists to manufacture amulti-piece dust shroud using an improved, cost-efficient process thatproduces a better dust shroud.

SUMMARY OF THE INVENTION

[0007] An aspect of the invention involves a dust shroud for use with avacuum source and an abrading machine having a rotating abrading wheel.The dust shroud includes a dust shroud housing adapted to be connectedto the vacuum source and mounted to the abrading machine. The dustshroud housing includes a front wall with a front opening through whichthe abrading wheel may be accessed. A sliding door is slidably mountedto the front wall of the dust shroud housing for selectively coveringthe front opening.

[0008] Another aspect of the invention involves a sliding door assemblyfor a dust shroud. The dust shroud is adapted for use with a vacuumsource and an abrading machine having a rotating abrading wheel. Thedust shroud includes a dust shroud housing having a front wall with afront opening through which the abrading wheel may be accessed. Thesliding door assembly includes a sliding door adapted to be slidablymounted to the front wall of the dust shroud housing for selectivelycovering the front opening. In one implementation, the front wall of thehousing includes a mounting portion integrated with the front wall, andthe sliding door is adapted to be slidably mounted to the mountingportion. In an alternative implementation, the sliding door assemblyfurther includes an adapter bracket adapted to be mounted to the frontwall and slidably receive the sliding door.

[0009] An additional aspect of the invention involves a method ofcontrolling the size of a front access opening of a front wall of a dustshroud, where the dust shroud is for use with a vacuum source and anabrading machine having a rotating abrading wheel. The method includesproviding a sliding door slidably mounted to the front wall of the dustshroud, and sliding the door to a location that minimizes theinterference with a workpiece, but maximizes vacuum suction. In oneimplementation, the dust shroud includes a mounting portion integratedwith the front wall, and providing a sliding door includes the step ofproviding a sliding door slidably mounted to the mounting portion. In analternative implementation, the dust shroud includes an adapter bracketmounted to the front wall, and providing a sliding door includes thestep of providing a sliding door slidably mounted to the adapterbracket.

[0010] A further aspect of the invention involves a method ofretrofitting a sliding door assembly to a dust shroud, where the dustshroud is for use with a vacuum source and an abrading machine having arotating abrading wheel. The dust shroud includes a dust shroud housinghaving a front wall with a front opening through which the abradingwheel may be accessed. The method includes removing a hinged door fromthe front wall of the dust shroud, and mounting a sliding door assemblyto the front wall, the sliding door assembly including an adapterbracket and a slidable door adapted to be slidably received by theadapter bracket.

[0011] Another aspect of the invention involves a method ofmanufacturing a dust shroud for use with a vacuum source and an abradingmachine having a rotating abrading wheel. The method includes diecasting a front dust shroud housing portion, die casting a rear dustshroud housing portion, and attaching the front and rear dust shroudhousing portions together to form a dust shroud housing.

[0012] An additional aspect of the invention involves a bracket assemblyfor mounting a dust shroud to an abrading machine. The dust shroudincludes an alignment bar. The abrading machine includes a spindlehousing with a circular portion surrounding a spindle adapted to carryan abrading wheel. The bracket assembly includes a circular clampsection adapted to be rotatably mounted to the circular portion of thespindle housing for rotatable angular adjustability of the dust shroudrelative to the abrading wheel, and a forked portion adapted to receivethe alignment bar of the dust shroud for radial adjustability of thedust shroud relative to the abrading wheel.

[0013] Another aspect of the invention involves a method of mounting adust shroud to an abrading machine. The method includes rotatablymounting a circular clamp section of a bracket assembly to a circularportion of a spindle housing of the abrading machine, and radiallymounting an alignment bar of the dust shroud to a forked portion of thebracket assembly.

[0014] A further aspect of the invention involves a bracket assembly formounting a dust shroud having an alignment bar to an abrading machinehaving a spindle housing with a spindle adapted to carry an abradingwheel. The bracket assembly includes a circular adapter adapted to bemounted to the spindle housing around the spindle, a bracket including acircular clamp section adapted to be rotatably mounted to the circularadapter for rotatable angular adjustability of the dust shroud relativeto the abrading wheel, and a forked portion adapted to receive thealignment bar of the dust shroud for radial adjustability of the dustshroud relative to the abrading wheel.

[0015] A still further aspect of the invention involves a method ofmounting a dust shroud to an abrading machine. The method includesmounting a circular adapter of a bracket assembly to a spindle housingof an abrading machine, around a spindle of the spindle housing,rotatably mounting a circular clamp section of a bracket to the circularadapter, and radially mounting an alignment bar of a dust shroud to aforked portion of the bracket.

[0016] Other features and advantages of the invention will be evidentfrom reading the following detailed description, which is intended toillustrate, but not limit, the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings illustrate the design and utility of preferredembodiments of the present invention, in which similar elements arereferred to by common reference numerals.

[0018]FIG. 1 is a cross-sectional view along the vertical centerline ofan embodiment of the dust shroud.

[0019]FIG. 2 is a cross-sectional view of the dust shroud along line 2-2of FIG. 1.

[0020]FIG. 3 is a cross-sectional view of the dust shroud along line 3-3of FIG. 1.

[0021]FIG. 4A is a front elevational view of the dust shroud of FIG. 1mounted to a grinding machine, and illustrates a sliding access door ina fully closed or lowered position.

[0022]FIG. 4B is a front elevational view of the dust shroud of FIG. 1mounted to a grinding machine, and illustrates the sliding access doorin a partially open or raised position.

[0023]FIG. 5 is a front elevational view of the dust shroud of FIG. 1,and illustrates the sliding access door is in a partially open or raisedposition.

[0024]FIG. 6A is a front elevational view of an embodiment of a bracketassembly for mounting the dust shroud of FIG. 1 to a grinding machine.

[0025]FIG. 6B is a cross-sectional view of the bracket assembly alongline 6B-6B of FIG. 6A.

[0026]FIG. 7A is a front side elevational view of a grinding machine,and illustrates the dust shroud of FIG. 5 and the bracket assembly ofFIG. 6A separated from the grinding machine.

[0027]FIG. 7B is a left side elevational view of the grinding machine,dust shroud and the bracket assembly illustrated in FIG. 7A.

[0028]FIG. 7C is a front side elevational view of the grinding machine,dust shroud and the bracket assembly illustrated in FIG. 7A with thedust shroud and bracket assembly assembled on the grinding machine.

[0029]FIG. 7D is a left side elevational view of the grinding machine,dust shroud and the bracket assembly illustrated in FIG. 7C with thedust shroud and bracket assembly assembled on the grinding machine.

[0030]FIG. 8 is an exploded cross-sectional view of an alternativeembodiment of a bracket assembly for mounting the dust shroud of FIG. 1to a grinding machine, and illustrates a portion of a spindle housing ofa grinding machine.

[0031]FIG. 9 is cross-sectional view the bracket assembly of FIG. 8assembled on a portion of a spindle housing of a grinding machine.

[0032]FIG. 10 is a perspective view of a grinding machine, andillustrates the dust shroud of FIG. 5 and the bracket assembly of FIGS.8 and 9 separated from the grinding machine.

[0033]FIG. 11 is a side-elevational view of an alternative embodiment ofa sliding door assembly, and illustrates the sliding access door in apartially open or raised position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT8

[0034] With reference to FIGS. 1-5, an embodiment of a dust shroud 10will now be described. The dust shroud 10 includes a dust shroud housing15 adapted for use with a remote vacuum source 20 for removingdust-laden air from the vicinity of an abrading machine such as agrinding machine 22 (FIGS. 4A, 4B) having a grinding wheel 60. Theremote vacuum source 20 is designed to draw dust, grit and metalparticles through the housing 15 to effectively control and eliminatedirty and hazardous dust laden air from the grinding machine work area.

[0035] In use, the dust shroud housing 15 is mounted on a spindlehousing 23 (FIGS. 7A, 7B) of a grinding machine 22. The spindle housing23 carries a rotating spindle that the grinding wheel 60 is mounted tofor rotation. The spindle housing 23 may be moved vertically away from aworkpiece 30 to represent an ascending movement of the wheel 60 andshroud 10 and toward the workpiece 30 to represent a descending movementof the wheel 60 and shroud 10. Rotation of the wheel 60, as shown by R,is generally in the clockwise direction.

[0036] The workpiece 30 may be held in place by a magnetic device 40 ona reciprocating table 50 of the machine 22.

[0037] The dust shroud 10 may be mounted to the spindle housing 23 by abracket assembly to be described. The dust shroud 10 surrounds themajority of the wheel 60. Generally, the housing 15 should enclose theentire top half of the wheel 60 and as much of the bottom half of thewheel 60 as is practical to avoid interference with the workpiece 30during grinding. Additionally, as described in more detail below, theshroud 10 may be angled and moved radially with respect to the wheel 60so that the shroud 10 can be adjusted to work effectively with wheels 60of different diameters and with workpieces 30 of different shapes andsizes, while covering as much of the wheel 60 as possible.

[0038] The dust shroud housing 15 preferably includes a two-piececonstruction comprising a front member 64 and a rear member 66. The twomembers 64, 66 are preferably die casted and made of aluminum. In analternative embodiment, the two members 64, 66 may be injection moldedand made of plastic as long as the material is sufficiently strongenough to withstand the impact of a disintegrating grinding wheel. Thetwo members 64, 66 may be aligned by various interlocking and sealingfeatures and connected with threaded fasteners through screw holes 25 toform the complete dust shroud housing 15.

[0039] In the past, dust shrouds such as that illustrated in U.S. Pat.No. 4,192,104 were sand casted using sand bonded with clay. Sand castingsuch a dust shroud is disadvantageous because the clay-bonded sandrequires moisture, which along with loose sand can cause various castingdefects. Additionally, a sand mold can only be used once because theheat of molten metal breaks clay bonds.

[0040] An advantage of the two-piece shroud 10 is that it permits easymaintenance, particularly when cleaning out accumulated dust and debrisfor maximum dust shroud efficiency because the two members 64, 66 can beseparated and cleaned.

[0041] Also, the two piece die cast aluminum construction is superior toprior art sand casted shrouds especially with respect to smoothness,accuracy and overall quality of the product. Because the die cast orplastic injection molded surfaces of the interior vacuum channels of theshroud 10 are considerably smoother than the sand cast surfaces of theprior art dust shrouds, increased airflow and, therefore, higher dustremoval rates are produced. Thus, a dust shroud housing 15 having moreefficient vacuum channel flow characteristics can be produced using thepresent die cast aluminum or plastic injection molded methods.

[0042] Another advantage of die casting and injection molding is theability to produce the shroud 10 with substantially thinner wallsections, greatly reducing the overall weight (approximately 15%) of theapparatus compared to comparable sand casted shrouds without sacrificingquality or functionality. Thus, less effort is required on behalf of amachine operator to adjust the dust shroud housing 15. Also, the lighterweight construction extends the life of all of the machine components,e.g., spindle height adjustment mechanisms, affected by premature wearand failure caused by the considerably heavier prior art devices.Additional advantages of utilizing die casting or injection moldinginclude higher production rates for mass production, closer tolerances,minimal subsequent machining and low part cost at high volumeproduction.

[0043] With reference to FIGS. 1-3 and 5, the shroud housing 15 includesopposite side walls 70, 80 comprising a far or rear side 70 and a nearor front side 80 having a wheel access opening 90. The housing 15 alsoincludes a left end wall 110 that connects the sides 70, 80, a right endwall 120 that connects the sides 70, 80, a contoured inclined upper topwall 130 that connects the sides 70, 80 and the front wall 120, and aninclined lower top wall 140 that connects the sides 70, 80 and mergeswith the upper portion of the left end wall 110. The left ending of eachof the top walls 130, 140 and the left ending of the upper portion ofeach side wall 70, 80 together define a tubular chamber section 150 inwhich all of a variety of vacuum channels connect and which may beconnected by piping 160 or other flexible hose means to the vacuumsource 20.

[0044] A primary vacuum channel 170 is defined by the sidewalls 70, 80and the lower left wall 110. A first internal wall 180 extends betweenthe sidewalls 70, 80 and is spaced appropriately in relationship to thetipper top wall 130 to form a secondary vacuum channel 190. The firstinternal wall 180 includes a right vertically curving extension 200 thatextends between the spaced sidewalls 70, 80 appropriately from andgenerally parallel to right wall 120 to define an extension andcontinuation of the secondary vacuum channel 190. The first internalwall 180 includes a left terminus that terminates adjacent to theprimary vacuum channel 170 and a right terminus in the form of a firstend wall portion 220 that extends between the lower extremities of thewalls 120, 200.

[0045] The wall section 200 has an opening 230 that allows vacuumsuction to pull the dust-laden air and other debris thrown off thegrinding wheel 60 into and through the secondary vacuum channel 190. Theopening 230 has a slightly narrower width than the width of the grindingwheel 60.

[0046] Extending left from the first internal wall 180 at approximatelythe point just before it starts to join the curved section of wall 200is a generally horizontally arranged second internal wall 240 extendingleft for a distance before it curves downward to a point 250. The secondinternal wall 240 is designed to follow the circumference of thegrinding wheel 60, when present, and has an opening 260 to allowadditional vacuum suction.

[0047] The construction of the dust shroud housing 15 is such thatdust-laden air is drawn through the vacuum channels 170, 190 divided bymeans of the internal walls 180, 240 having openings 230, 260 within theinterior of the housing 15. These openings 230, 260 are strategicallyarranged around the perimeter of the grinding wheel 60 so as to pulldust laden air away from the rotating grinding wheel 60 and through thevacuum channels 170, 190. Preferably, the openings 230, 260 are narrowedslots that restrict the air flow therethrough so that the pressurethroughout the system is increased, thereby triggering an increase inair velocity and overall suction effect. Because the openings 230, 260are centered around the periphery of the grinding wheel 60, maximumsuction pressure is created along the perimeter of the wheel 60 wherethe highest concentration of dust and debris is centered. Ultimately,the dust-laden air is sucked through the tubular chamber section 150,out of the housing 15, and into the vacuum source 20.

[0048] With reference specifically to FIG. 1, the rotation R of thegrinding wheel 60 is in a clockwise direction such that the greaterportion of the dust generated by the grinding machine is drawn left,away from the wheel 60 between the 6 o'clock and 12 o'clock positionsthrough the primary vacuum channel 170. Other portions of the dust-ladenair not initially pulled from the rotating wheel 60 or the air cushionorbiting around it between the 6 and 12 o'clock positions will beremoved from the wheel 60 through the secondary vacuum channel 190. Theopenings 230, 260 in the internal walls 180, 240 are designed to takeadvantage of the air speed generated by the centrifugal force of therotating grinding wheel 60 to increase the suction power and improve theefficiency of the dust shroud.

[0049] With reference additionally to FIG. 3, the width of the opening260 is much narrower than the width of the grinding wheel 60 so as todefine baffle means 270 at opposite sides of the wheel 60 in the form ofwall portions 270. The baffle means 270 serve to concentrate the suctionpower from the vacuum source 20 onto the circumference of the rotatinggrinding wheel 60. As the grinding wheel 60 contacts the workpiece 30and shards of debris fly off the workpiece 30, some of the shards arecast into the primary vacuum channel 170 and drawn into the vacuumsource 20. Meanwhile, other shards of debris that remain attached to thegrinding wheel's porous surface as the grinding wheel 60 rotates aroundto opening 230 are eventually pulled through the opening 230 intosecondary vacuum channel 190 and swept into the vacuum source 20.

[0050] The rear wall 70 of the housing 15 has an alignment bar 280 (FIG.3) comprising a vertically elongated protrusion having a threaded hole290 near its midpoint. The alignment bar 280 is used to align and mountthe shroud 10 to the spindle housing 23 (FIGS. 10, 11) of the grindingmachine 22 through a bracket assembly to be described.

[0051] With reference to FIG. 1, the shroud housing 15 may include oneor more indicator mounting holes 294 for accommodating indicators orother accessories used to assist in grinding. Any of a variety ofmeasurement or checking devices routinely used to align the workpiece 30with the grinding wheel 60 may be attached to the shroud 10 using theindicator mounting holes 294. Locking screws 296 or other fasteners maybe used to lock such a measurement device(s) within the indicatormounting holes 294. The mounting holes 294 provide a simple andconvenient way to attach measurement or checking devices, improvingoperator efficiency and productivity.

[0052] With reference to FIGS. 6A, 6B and 7A-7D, an embodiment of anattachment bracket assembly 300 will now be described. In a preferredembodiment, the attachment bracket assembly 300 includes an attachmentbracket 302 that permits angular and radial adjustability of the dustshroud 10 with respect to the grinding wheel 60. The attachment bracket302 includes a flat shroud-mounting section 310. The shroud-mountingsection 310 is forked and includes arms 315 separated by an elongatedslot 320. The arms 315 may include one or more hollow sections 317 toreduce the weight of the bracket 302. The elongated slot 320 is adaptedto receive the alignment bar 280 of the shroud 10. The attachmentbracket 302 also includes a circular clamp section 330 adapted to beclamped about a circular portion 332 (FIGS. 7A, 7B)of the spindlehousing 23. Preferably, the bracket 302 is die casted and made ofaluminum.

[0053] In use, the shroud 10 may be mounted to the bracket 302 bysliding the alignment bar 280 within the slot 320 a distancecorresponding to a desired shroud height level. A threaded fastener (notshown) having an oversized head may be inserted through the slot 320 andthreadably attached to the threaded hole 290 in the alignment bar 280 inorder to secure the shroud 10 at a preferred radial distance relative tothe grinding wheel 60. The circular clamp 330 may be slid over thecircular portion 332 of the spindle housing 23 and rotated at a desiredangle relative to the wheel 60 and workpiece 30. To maintain the bracket302 and shroud 10 in this position around the circular portion 332 ofthe spindle housing 23, a threaded fastener 340 is tightened, causingthe clamp 330 to tighten around the circular portion 332. Loosening thethreaded fastener 340 allows an operator to angularly adjust the shroud10 about the circular portion relative to the workpiece 30. Thus, thebracket 302 is multi-functional in that it allows radial and angularadjustability of the shroud 10 relative to the grinding wheel 60,allowing workpieces 30 of a variety of configurations to be worked onwith minimal or no interference from the shroud 10.

[0054] In an alternative embodiment, the shroud 10 may be mounted to thespindle housing 23 by, first, attaching the clamp 340 of the bracket 302to the circular portion 332 of the spindle housing 23 at a desired anglerelative to the wheel 60, and, then, mounting the shroud 10 to thebracket 302 at a desired radial distance relative to the wheel 60.

[0055] With reference to FIGS. 8-10, an alternative embodiment of anattachment bracket assembly 335 will now be described. The attachmentbracket assembly 335 is a two-piece attachment bracket assembly thatallows for radial and angular adjustability of the shroud 10 where acircular portion 332 (FIGS. 7A, 7B) of sufficient dimensions does notexist on the spindle housing 23 of the grinding machine 22 for mountingthe clamp 330 thereto. The attachment bracket assembly 335 includes theaforementioned attachment bracket 302 and a circular adapter 350configured to be mounted to a front face 352 of the spindle housing 23.The circular adapter 350 is designed to be disposed between theattachment bracket 302 and the spindle housing 23. The circular adapter350 includes a stepped concentric protrusion 355 dimensioned to bereceived by a stepped concentric recession 365 in the attachment bracket302 such that rotation of the attachment bracket 302 relative to theadapter 350 is permitted. The adapter 350 further includes a pluralityof threaded fastener holes 360 adapted to receive threaded fasteners formounting the adapter 350 to a front face 352 of the spindle housing 23.

[0056] In use, the adapter 350 is mounted to the spindle housing 23 withmultiple threaded fasteners. Then, as described above, the bracket 302is mounted to the shroud 10 followed by the bracket 302 being mounted tothe adapter 250. Alternatively, the bracket 302 may be mounted to theadapter 350 followed by the shroud 10 being mounted to the bracket 302.

[0057] With reference to FIGS. 4A, 4B and 5, an embodiment of a slidingdoor assembly 400 for the dust shroud 10 will now be described. Thesliding door assembly 400 includes a sliding access door 405 forselectively covering the opening 90 on the front side 80 of the dustshroud housing 15. The sliding door 405 includes a pair of elongateddovetail projections 410 on opposite sides of the sliding access door405. A mounting portion 415 on the front side 80 of the housing 15includes dovetail slots 420 located at opposite sides of the opening 90that define opposite sides of the opening 90 and slidably receive thecorresponding dovetail projections 410 of the sliding door 405. Themounting portion 415 may be formed integrally with the rest of the diecasted shroud 10. By inserting the dovetail projections 410 into thedovetail slots 420, the door becomes vertically slidable within themounting portion 415. The sliding action of the door 405 allows anoperator to selectively position the door 405 in an infinite number ofpositions between a closed position, where the bottom of the door 405 isflush with the bottom of the shroud housing 15, and an open position,where the door 405 covers little or none of the grinding wheel 60.

[0058] The sliding door assembly 400 further includes a clampingarrangement 430 for securing the door 405 in place once a desired doorheight level or position is obtained. The clamping arrangement 430includes a mounting plate 440, a washer (not shown) and a threadedfastener 460 adapted to be screwed into a threaded hole (not shown) inthe front side 80 of the housing 15. The threaded fastener 460 includesan oversized, plastic head 480 to facilitate turning without the use oftools. Turning the fastener 460 clockwise a sufficient amount within thethreaded hole urges the mounting plate 440 against the sliding accessdoor 405, and secures the door 405 in position. Likewise, sufficientturning of the fastener 460 in a counter-clockwise direction looses themounting plate 440, allowing the door 405 to slide within the mountingportion 415. It will be readily apparent to those skilled in the artthat other clamping arrangements or door securing mechanisms may beused.

[0059] The sliding access door 405 may include a stop assembly (notshown) that prevents the door 405 from sliding too far down and/or ortoo far up. The sliding access door 405 may also include a handle 495that projects outwardly from the top edge of the door 405 to facilitatevertical movement of the door by an operator. Although a handle 495 isshown at the top of the door 405, it will be readily apparent to thoseskilled in the art that the handle may be located at other locations onthe door 405 such as, but not by way of limitation, the bottom of thedoor 405. Further, the handle 495 may include alternativeconfigurations.

[0060] The sliding access door 405 is a significant improvement overprior hinged doors for grinding machine dust shrouds because the hingeddoors could only be either fully opened or closed. If the hinged doorwas closed, it would often interfere with the workpiece 30 duringgrinding. If the hinged door was open, insufficient vacuum suctionoccurred in the shroud. The sliding access door 405 along with theclamping arrangement 430 allows the user to selectively position thedoor 405 so that the door 405 is high enough that the door 405 does notinterfere with the workpiece 30 during grinding, but low enough thatmaximum vacuum suction occurs in the shroud 10, allowing the shroud tofunction as intended. During use, the door 405 may be opened only as faras necessary to facilitate the changing of grinding wheels, wheeldressing, and checking or measuring of the workpiece 30.

[0061] By using the improved, infinitely adjustable sliding access door405, several advantages can be realized. First, wheel changing,inspection, measurement of the workpiece 30 and overall operatorefficiency can be simplified and facilitated due to the ease ofoperation of the sliding door 405 and the ability to lock the door 405at any height level. Second, dust and debris levels in the air can besignificantly reduced because a higher volume of dust-laden air can beremoved with a partially opened door that allows maximum vacuum suctionthan can be removed with prior art doors in the fully open position.Thus, an operator can open the sliding door 405 only as far as necessaryto take advantage of the fullest measure of vacuum suction power toimprove the condition of the ambient air surrounding the operator.

[0062] With reference to FIG. 11, an additional embodiment of a slidingdoor assembly 500 for a dust shroud will now be described. The slidingdoor assembly 500 is preferably used for retrofitting an existing dustshroud such as the dust shroud shown and described in U.S. Pat. No.4,192,104 to Patenaude. The sliding door assembly 500 includes theaforementioned sliding access door 405 and an adapter bracket 505. Theadapter bracket 505 is adapted to be retrofitted to an existing dustshroud and forms a mounting portion for slidably mounting the accessdoor 405 to the dust shroud 10. The adapter bracket 505 is preferablydie casted and made of aluminum. The adapter bracket 505 includes a leftleg 510, a right leg 520 and a top connecting portion 530. An elongated,arcuate inward projection 540 extends along the bottom of the topconnection portion 530 between the left leg 510 and the right leg 520.The bracket legs 510, 520 include inwardly projecting elongated dovetailslots 545 adapted to slidably receive the corresponding elongateddovetail projections 410 of the sliding access door 405. The adapterbracket 505 preferably includes a clamping arrangement 550 similar tothe clamping arrangement 430 described above with respect to FIG. 5. Thesliding door assembly 500 may include a stop assembly that prevents thedoor 405 from sliding too far down and/or or too far up. For example arear side of the access door 405 may include a projection (not shown)that is adapted to abut a catch 555 in the top connecting portion 530 ofthe adapter bracket 505 when the door 405 is slid downward in theadapter bracket 505.

[0063] A method of retrofitting the sliding door assembly 500 to anexisting dust shroud will now be described. First, a hinged door fromthe front wall of the existing dust shroud is unfastened and removed.Next, the adapter bracket 505 is mounted to the front wall of the dustshroud. The adapter bracket 505 is preferably mounted to the front wallaround the access opening by affixing the adapter bracket 505 to thefront wall with an epoxy resin or silicone sealer. It will be readilyapparent to those skilled in the art that other mounting methods may beused. For example, the bracket 505 may be welded, bolted, or screwed tothe front wall. If the door 405 is already slidably attached to theadapter bracket 505, retrofitting may end here. If the door 405 is notalready slidably attached to the adapter bracket 505, the door 405 maybe slidably mounted to the adapter bracket 505 by slidably inserting thedoor into to the top of the adapter bracket 505.

[0064] While preferred embodiments and methods have been shown anddescribed, it will be apparent to one of ordinary skill in the art thatnumerous alterations may be made without departing from the spirit orscope of the invention. Therefore, the invention is not limited exceptin accordance with the following claims.

I claim:
 1. A dust shroud for use with a vacuum source and an abradingmachine having a rotating abrading wheel, comprising: a dust shroudhousing adapted to be connected to the vacuum source and mounted to theabrading machine, said housing including a front wall with a frontopening through which the abrading wheel may be accessed; and a slidingdoor slidably mounted to said front wall of said dust shroud housing forselectively covering said front opening.
 2. The dust shroud according toclaim 1, wherein said sliding door is slidably mounted to said frontwall of said dust shroud housing for selective vertical heightadjustment of said front opening.
 3. The dust shroud according to claim1, wherein said front wall of said housing includes a mounting portionadapted to slidably receive said sliding door.
 4. The dust shroudaccording to claim 3, wherein said mounting portion is integral withsaid front wall.
 5. The dust shroud according to claim 3, wherein saidmounting portion includes an adapter bracket adapted to slidably receivesaid sliding door.
 6. The dust shroud according to claim 5, wherein saidadapter bracket comprises a curvilinear aluminum bracket having a leftleg, a right leg and a top connecting portion.
 7. The dust shroudaccording to claim 5, wherein said adapter bracket and sliding door areadapted to be retrofitted onto an existing dust shroud.
 8. The dustshroud according to claim 5, wherein said adapter bracket is adapted tobe affixed to the front wall of said housing.
 9. The dust shroudaccording to claim 5, wherein said adapter bracket is adapted to befixed to the front wall of said housing with one or more fasteners. 10.The dust shroud according to claim 2, wherein said mounting portionincludes a sliding door position control mechanism for controlling theposition of said sliding door.
 11. The dust shroud according to claim10, wherein said sliding door position control mechanism is anadjustable clamp.
 12. The dust shroud according to claim 2, wherein saidsliding door is adapted to be removed entirely from said shroud.
 13. Thedust shroud according to claim 1, wherein said housing is a die castaluminum construction.
 14. The dust shroud according to claim 13,wherein said die cast aluminum construction is a two-piece constructionincluding a front housing and rear housing.
 15. The dust shroudaccording to claim 14, wherein said front housing and rear housing arefastened together to form said housing.
 16. The dust shroud according toclaim 1, further comprising a bracket assembly adapted to couple saiddust shroud to said abrading machine.
 17. The dust shroud according toclaim 16, wherein said bracket assembly allows relative angular rotationand radial movement of said dust shroud relative to said abrading wheel.18. The dust shroud according to claim 17, wherein said bracket assemblyincludes a first circular clamp section adapted to be mounted to saidabrading machine and a second clamp section rotatably mounted to saidfirst circular clamp and adapted to be mounted to said dust shroud. 19.The dust shroud according to claim 1, wherein said front wall furthercomprises a plurality of indicator mounting holes adapted to receive aworkpiece measurement or checking device.
 20. A sliding door assemblyfor a dust shroud, the dust shroud adapted for use with a vacuum sourceand an abrading machine having a rotating abrading wheel, the dustshroud including a dust shroud housing having a front wall with a frontopening through which the abrading wheel may be accessed, comprising: asliding door adapted to be slidably mounted to said front wall of saiddust shroud housing for selectively covering said front opening.
 21. Thesliding door assembly according to claim 20, wherein said sliding dooris adapted to be slidably mounted to said front wall of said dust shroudhousing for selective vertical height adjustment of said front opening.22. The sliding door assembly according to claim 20, wherein said frontwall of said housing includes a mounting portion integral with saidfront wall, and said sliding door is adapted to be slidably mounted tosaid mounting portion.
 23. The sliding door assembly according to claim20, further including an adapter bracket adapted to mounted to saidfront wall and slidably receive said sliding door.
 24. The sliding doorassembly according to claim 23, wherein said adapter bracket comprises acurvilinear aluminum bracket having a left leg, a right leg and a topconnecting portion.
 25. The sliding door assembly according to claim 23,wherein said adapter bracket and sliding door are adapted to beretrofitted onto an existing dust shroud.
 26. The sliding door assemblyaccording to claim 23, wherein said adapter bracket is adapted to beaffixed to the front wall of said housing.
 27. The sliding door assemblyaccording to claim 23, wherein said adapter bracket is adapted to befixed to the front wall of said housing with one or more fasteners. 28.The sliding door assembly according to claim 20, further including asliding door position control mechanism adapted for controlling theposition of said sliding door.
 29. The sliding door assembly accordingto claim 28, wherein said sliding door position control mechanism is anadjustable clamp.
 30. The sliding door assembly according to claim 20,wherein said sliding door is adapted to be removed entirely from saidshroud.
 31. A method of controlling the size of a front access openingof a front wall of a dust shroud for use with a vacuum source and anabrading machine having a rotating abrading wheel, comprising: providinga sliding door slidably mounted to said front wall of said dust shroud;and sliding the door to a location that minimizes the interference witha workpiece, but maximizes vacuum suction.
 32. The method according toclaim 31, wherein sliding the door includes the step of verticallysliding the door to a desired height.
 33. The method according to claim31, wherein said dust shroud includes a mounting portion integrated withsaid front wall, and providing a sliding door includes the step ofproviding a sliding door slidably mounted to said mounting portion. 34.The method according to claim 31, wherein said dust shroud includes anadapter bracket mounted to said front wall, and providing a sliding doorincludes the step of providing a sliding door slidably mounted to saidadapter bracket.
 35. The method according to claim 31, further includinglocking the position of said sliding door to a desired position using asliding door position control mechanism.
 36. The method according toclaim 31, wherein sliding said sliding door includes removing saidsliding door entirely from said front wall.
 37. A method of retrofittinga sliding door assembly to a dust shroud for use with a vacuum sourceand an abrading machine having a rotating abrading wheel, the dustshroud including a dust shroud housing having a front wall with a frontopening through which the abrading wheel may be accessed, comprising:removing a hinged door from said front wall of said dust shroud;mounting a sliding door assembly to said front wall, the sliding doorassembly including an adapter bracket and a slidable door adapted to beslidably received by said adapter bracket.
 38. The method according toclaim 37, wherein said adapter bracket comprises a curvilinear aluminumbracket having a left leg, a right leg and a top connecting portion. 39.The method according to claim 37, wherein mounting an adapter bracket tosaid front wall includes the step of affixing said adapter bracket tothe front wall of said housing.
 40. The method according to claim 37,wherein mounting an adapter bracket to said front wall includes the stepof fixing said adapter bracket to the front wall of said housing withone or more fasteners.
 41. A method of manufacturing a dust shroud foruse with a vacuum source and an abrading machine having a rotatingabrading wheel, comprising: die casting a front dust shroud housingportion; die casting a rear dust shroud housing portion; and attachingthe front and rear dust shroud housing portions together to form a dustshroud housing.
 42. The method of claim 41, wherein the front and reardust shroud housing portions are made of aluminum.
 43. The method ofclaim 41, wherein attaching includes the step of attaching said fronthousing and said rear housing together with one or more threadedfasteners.
 44. A method of manufacturing a dust shroud for use with avacuum source and an abrading machine having a rotating abrading wheel,comprising: injection molding a front dust shroud housing portion;injection molding a rear dust shroud housing portion; and attaching thefront and rear dust shroud housing portions together to form a dustshroud housing.
 45. The method of claim 44, wherein the front and reardust shroud housing portions are made of plastic.
 46. The method ofclaim 44, wherein attaching includes the step of attaching said fronthousing and said rear housing together with one or more threadedfasteners.
 47. A bracket assembly for mounting a dust shroud having analignment bar to an abrading machine having a spindle housing with acircular portion surrounding a spindle adapted to carry an abradingwheel, comprising: a circular clamp section adapted to be rotatablymounted to said circular portion of the spindle housing for rotatableangular adjustability of the dust shroud relative to the abrading wheel;and a forked portion adapted to receive the alignment bar of the dustshroud for radial adjustability of the dust shroud relative to theabrading wheel.
 48. A method of mounting a dust shroud to an abradingmachine, comprising: rotatably mounting a circular clamp section of abracket assembly to a circular portion of a spindle housing of theabrading machine; radially mounting an alignment bar of the dust shroudto a forked portion of the bracket assembly.
 49. A bracket assembly formounting a dust shroud having an alignment bar to an abrading machinehaving a spindle housing with a spindle adapted to carry an abradingwheel, comprising: a circular adapter adapted to be mounted to thespindle housing around the spindle; a bracket including a circular clampsection adapted to be rotatably mounted to said circular adapter forrotatable angular adjustability of the dust shroud relative to theabrading wheel, and a forked portion adapted to receive the alignmentbar of the dust shroud for radial adjustability of the dust shroudrelative to the abrading wheel.
 50. A method of mounting a dust shroudto an abrading machine, comprising: mounting a circular adapter of abracket assembly to a spindle housing of an abrading machine, around aspindle of the spindle housing; rotatably mounting a circular clampsection of a bracket to said circular adapter; radially mounting analignment bar of a dust shroud to a forked portion of the bracket.